FIGHTING FITS

 
 

"Although frightening, epileptic fits in dogs can be treated with drugs"- Report presented to the British Veterinary Association conference by Geoff Skerritt FRCVS.1996.
 
 

About the author- Geoff Skerritt graduated from Liverpool University and has since achieved specialist status in veterinary neurology. He is now principal of a first opinion and referral practice on the Wirral, Cheshire.
 
 

Opening his talk, Mr Skerrit said that there are many potential causes of epilepsy and so each case of a dog suffering from seizures represents a diagnostic and therapeutic challenge.
Observant owners who are able to communicate with the vet are vital in helping to achieve successful management of the case.

Mr Skerritt said that a survey has shown that one dog in a hundred suffers from seizures at some time and that seizures can represent a significant proportion of the case load of vets in general practice. Yet the vet rarely witnesses a seizure in an individual patient and even the owners do not always know when their dog has had a fit, because the seizures often take place when the dog is asleep. It was suggested that owners try to video what they thought to be a fit incase they are misinterpreting what has taken place. The veterinary surgeon will need to know how long the seizure lasted, how frequent and severe the incident is, when it occurs, and how the dog behaved just before and after the seizure as well as any possible trigger factors for the seizure


Definition

A seizure (also called a fit) is a sudden episode of uncontrolled electrical activity of the brain. Recurrent seizures are called epilepsy. In a partial seizure abnormal
electrical activity is confined to just one part of the brain.
The patient may experience tingling or twitching of a small part of the head or body or feet. Sometimes sufferers hallucinate or experience intense fear.

Explaining Seizures.

In a generalised seizure, abnormal electrical activity spreads throughout the brain. This causes loss of consciousness and jerky muscle contractions, during which control may be lost of urine and faecal output. A single seizure may have several different causes and is not necessarily epilepsy. A sudden collapse may be due to fainting, heat stroke or hypoglycaemia, lack of oxygen, kidney failure or a heart problem. When the cause of the seizure is metabolic, the timing may be related to
feeding or exercise. Seizures that result from poisoning (e.g. organophosphates) may occur at any time of the day or night. 

Causes

Geoff Skerritt said it is important for the owners to be able to give a full medical history of the dog, including vaccination status, since fits are often associated with distemper which may have occurred years before. Trauma such as being violently hit on the head or neck or injury occurring when being thrown from a car in an accident may be reflected in seizures starting up to 2 years later.

If the owner is able to give some information about the birth of the dog this may be helpful, for trauma and lack of oxygen at birth may be responsible for the development of epilepsy later on. However, if the dog has been purchased this information is unlikely to be forthcoming and even if the breeder still owns the dog, he or she may not be able to remember which puppy in the litter needed to be revived.


Breeds

Mr. Skerritt observed that while there were few breeds in which epilepsy had not been recorded, some breeds do show a high incidence of seizures and in these an inherited pre disposition is suspected. So far inheritance has only been proven in a handful of breeds and it appears that it varies in complexity in different breeds. GSD's and Golden Retrievers are particularly prone to 'cluster seizures' which may mean three or four seizures or may be as many as 20-30 in a period of 24 hours, and then a period of 2-3 weeks without fits. Clustering should be regarded as a poor sign because status epilepitcus (one seizure following another in rapid succession without the dog regaining consciousness between fits) is a likely sequel. Any seizure which lasts for longer than 5 minutes may become status epilepticus and that is a very serious condition.

The onset of primary seizures usually occurs between the ages of  1 and 3 years old, but in the larger breeds e.g.. GSD's and Irish Setters seem to start as early as 6 months old and sometimes not until 6 years of age.

Mr Skerritt said that if seizures occur in a dog of less than 6 months old, or older than 6 years, a cause other than primary epilepsy should be suspected.


Investigation

Since most dogs who suffer from seizures are taken to the vet when they are not having a fit, they will probably appear to be clinically normal, so a thorough physical examination is carried out to eliminate any causes of seizures which do not involve brain activity. Biochemical profiles will eliminate other causes, and CSF taken from the back of the neck will indicate whether any other brain disorder such as tumour, may be responsible for the seizure. Mr Skerritt said that the difficulty of interpreting EEG have caused that procedure to fall out of favour. In his experience most primary epileptics record normal EEG's when they are not having fits. The EEG is of no use for detecting the potential for epilepsy in clinically normal animals, although there was a time 20 or more years ago when this procedure was thought to have been of some use.

Therapy.

There are a number of drugs that will control the frequency of fits in dogs, to a degree which improves the quality of life for the dog. However Mr. Skerritt warned that pet owners should be made aware that seizures will not be completely eliminated, although this has been successful in some cases. Once started, anticonvulsant therapy must be continued, probably for years as it is difficult to stop the therapy without inducing a seizure. The best drug to use is one that has minimal side effects, is tolerated well and is inexpensive. Phenobarbitone recently licensed for veterinary use in the UK as Epiphen, is a drug of choice, but it must be given regularly as the effect wears off quickly. Side effects in some individual dogs may be initially  sedation, increased eating and drinking, and excitement but these effects usually wear off in a week or two on the drug.

Definition.

Mysoline, Epanutin, and Potassium Bromide are also used, but Diazepam (Valium) has not proved effective as it is quickly metabolised in dogs and very frequent dosing would be necessary to reach a therapeutic level. Some dogs do not respond to treatment, no matter how carefully the owners administer the prescribed medication, Mr Skerritt concluded Uncontrollable status epilepticus is often the sequel, or the owner is understandably unable to manage a dog which has frequent and violent seizures.

Kennel Gazette Jan. 1997.